Bolt.



No. 857.295. PATENTED JUNE 18, 1907. H. H. MUDGE. Q -120m. APPLIGATIORFILED JULY 26, 1906. l

HENRY I-I; MUDGE, OF BRISTOL, RHODE ISLAND.

BOLT.

Specification of Letters Patent.

Patented June 18, 1907.

Application filed July 26,1906. Serial No. 327.932.

To (LZZ whom, it 7n concern-r Be it known that I, HENRY H. M DGE, acitizen of the United States, residingat Bristol, in the county ofBristol and State of Rhode Island, have invented new and usefulImprovements in Bolts, of which the following is a specification.

My invention relates to a bolt adapted to a great variety of uses indrawing or binding together two objects, its construction including ashank tubular throughout, with its lower end fitted to screw into atapped hole of one of the bodies to be united, while the head of thebolt is conical and also tubular or provided with a cavity preferably ofinverted pyramidal form. The bolt head is or may befurnished with a cap,stopper or plug adapted to close the head cavity so as to prevent theentrance of extraneous matter thereto and to the tubular shank, and inconsequence to the tapped hole in which the lower end of the bolt fits.

My improved bolt isintended to be screwed into and withdrawn from theinner one of two bodies through the medium of a wrench or turn screwwhichfits the head and a cer tain portion of the tubular shank, the boreof which is of square, triangular or other ,polygonal shape in crosssection.

I-Ieretofore hollow screws, more particularly set screws, have beenknown, and I do not broadly claim a screw having a hollow shank capableof receiving a wrench or other instrument for attaching it to orremoving it from a threaded body; my invention being shown in theaccompanying drawings, described in the explanation thereof whichfollows, and more particularly pointed out in the claims of invention atthe end hereof.

In the drawin Figure 1 shows, partly in section, the hea ed end of acylinder, such for example, as is used in gasolene driven automobiles towhich my invention is applied in the attachment of the head to thecylinder. Fig. 2 is a plan view of Fig. 1. Fig. 3 is a section showing amodification of a fea- 'ture illustrated in Fig.- 1. Fig. 4 shows amodified form of the head of the bolt. Figs. 5 and 6 indicate wrenchesor turn screws suited for use with my improved bolt.

Similar reference characters indicate similar parts in the respectivefigures.

While my invention is here shown as applied to the attachment of a headto its cylinder, it is obvious it is not limited to this specialpurpose, this mode of use being presented as one simple and conventionalin type.

Let 1 re resent a cylinder and 2 its head. The cylin er and head areunited as shown by four bolts each of which enters a threaded or tappedhole in the end of the cylinder, and

is constructed as follows: 3 is the hollow bolt the portion from a to bof which is that comprised between the point at which the thread beginsand the head. The head 4 is conical and provided with a squared orinverted pyramidal cavity 1 which at the bottom registers and agrees inshape with the aperture or bore 4 through the shank of the bolt. Theportion of the latter from b to c is threaded and enters the tapped hole5 in the end of the cylinder or other part to which the detachablemember 2 is to be affixed or drawn.

' In Fig. 1, 6 represents a cap, stopper or plug of shape conforming tothat of the cavity 4 in the head 4 of the bolt, but preferably of aboutone-half its depth and which is fitted to the cavity as shown. In theform of cap seen in Fig. 1, a wall of the cavity 4 is provided withanotch 4 which fits the tongue 7 of a finger lever 7 pivoted at 7 withina slot in the cap as shown, the tongue being prefer ably forced into thenotch through the medium of a spring 7. In Fig. 3 a cap 6" is shown amodification having resilient prongs 8 which extend through the cavityin the head of the bolt and engage sides of the bore in the shank. Anyform of ca stopper or plug may be employed provide it is adapted to beheld within the head and to be readily withdrawn therefrom. i In Fig. 4the head of the bolt is not conical but rounded and with a flat bearingsurface.

In Figs. 5 and 6 two forms of wrenches or turn screws are shown, Fig. 4indicating one .with a single and Fig. 2 one with a double all torsionalstrain thereupon being avoided.

The head of the screw constituting this invention being provided with asquare or in- 'verted pyramidal cavity, the bottom of upper portion ofthe wrench or turn screw adapted to fit the cavity in the head conformsto its shape, the wrench is firmly seated in the screw both at the headand throughout the length of the shank, and that in forcing the screw toor removing it from a body the strength of the screw or its head is notimpaired. The same advantageous result follows Whether the bore in theshank and the cavity in the head are of other polygonal shape. In allcases the cavity in the head, diminishing in size from the top to thebottom, corresponds in cross section to the shape of the bore of theshank, the sides of the cavity registering with those of the bore.

Ordinarily, in tightening a nut on a solid bolt, if much force is usedthe bolt is broken and usually where the two pieces of iron boltedtogether are contiguous. The piece of the bolt remaining in the standingpart is removed with difiiculty, it being necessary to drill a hole inthe part, and the threads are usually damaged. For example, in-Fig. 1the ordinary solid bolt would be screwed into the cylinder and thecylinder head bolted on by means of a nut engaging the end of the boltextending through the registering hole in the cylinder head. When such abolt is broken the break generally occurs where the bolt enters thecylinder, and when it is drilled out the threads in the hole in thecylinder are apt to be more or less damaged and their holding strengthon a new bolt impaired. But if a break occur in my hollow bolt, it isobvious the broken part may be easily removed without taking the engineapart. Such constructions as these render my improved bolt valuable inmany ways.

I do not restrict myself to the exact details of construction,combination and arrangement herein set forth, it being obvious thatminor variations thereof, not involving the exercise of invention, maybe made by the skilled mechanic; and such departures from what is hereindescribed and claimed, not involving invention, I consider as within thescope and terms of my claims.

Having thus described my invention, I claim 1. A bolt adapted to draw orbind together two bodies, said bolt having a shank threaded at its lowerpart and provided throughout its length with a bore of polygonal shape,and a head furnished with a cavity diminishing in size from. the top tothe bottom and corresponding in cross section to the shape of the boreof the shank, the sides of the cavity registering with those of saidbore, substantially as set forth.

2. A bolt adapted to draw or bind together two bodies, said bolt havinga shank threaded at its lower part andprovided throughout its lengthwith a bore of polygonal shape, and a head furnished with a cavitydiminishing in size from the top to the bottom and corresponding incross section to the shape of the bore of the shank, the sides of thecavity registering with those of said bore, combined with a tapered caphaving sides fitting the sides of the cavity of the head and furnishedwith a spring locking device, substantially as set forth. In testimonywhereof I affix my signature in presence of two witnesses.

HENRY H. MUDGE.

Witnesses:

A. O. POWELL, ANNE CONNOR.

